Video games that employ virtual reality and motion sensors have been shown to help stroke victims recover function in their debilitated limbs. Now a study published in Neural Regeneration Research showed that even a simple game that millions of people have played on their iPhone or iPad can help stroke patients’ brains.

The small study comprised of 18 healthy volunteers between 49 and 72 years old, plus five patients who had recently suffered a stroke. The researchers took fMRI scans of the test subjects’ brains before and after training them to play Fruit Ninja, a popular game that requires players to “slice” fruit. While the mobile version of the game asks players to slice the fruit by swiping on the touchscreen, the researchers in this study used Xbox Kinect, asking players to swipe their hands in front of the motion sensor to cut the fruit.

After the test subjects practiced at Fruit Ninja for an hour a day, five days a week for three weeks, the stroke patients showed improvements in upper limb function. (The improvements are measured using a variety of parameters, including the speed at which the patient can operate the arm, the ability to separate fingers individually, and dexterity in grasping and pinching.) The paper notes that several patients were interested in continuing the Fruit Ninja therapy even after the study was over, and they also requested a wider variety of games.

So what happens when stroke patients swipe digital fruit? Comparing the “before” and “after” fMRI scans of patients’ brains, the researchers observed changes in activity in the primary sensorimotor cortex, supplementary motor area and cerebellum areas, suggesting that the video game therapy helps to reorganize the brain’s neural structure to cope with stroke-induced impairments. Those observations are in line with previous studies which suggested that other therapies, including music therapy, are associated with stronger connectivity and improved activations of the motor cortex. By understanding the mechanisms that guide recovery, the researchers hope doctors will be able to predict outcomes and promote strategies that encourage brain repair.

Other studies have compared the effectiveness of virtual reality therapies, and found they may be more effective than other tedious physical therapies that rely on repetitive exercises. The authors of the current study suggest there are two reasons for its effectiveness: “First, auditory and visual stimulation in the games are attractive,” they write. “And second, when patients win or lose, they can obtain feedback information and inspiring sounds from the Kinect-based virtual reality game to encourage them to repeat the same motion.”

This article was originally written by Sarah Fecht for Popular Mechanics and can be found here.